function ScreenSaver(settings){     

        this.settings = settings;     

        this.nTimeout = this.settings.timeout;     

        document.body.screenSaver = this;

        // link in to body events

        document.body.onmousemove = ScreenSaver.prototype.onevent;

        document.body.onmousedown = ScreenSaver.prototype.onevent;

        document.body.onkeydown = ScreenSaver.prototype.onevent;

        document.body.onkeypress = ScreenSaver.prototype.onevent;     

        var pThis = this;

        var f = function(){pThis.timeout();}

        this.timerID = window.setTimeout(f, this.nTimeout);

    }

    ScreenSaver.prototype.timeout = function(){

        if ( !this.saver ){

            window.location = 'www.baidu.com';

        }

    }

    ScreenSaver.prototype.signal = function(){

        if ( this.saver ){

            this.saver.stop();

        }     

        window.clearTimeout(this.timerID);     

        var pThis = this;

        var f = function(){pThis.timeout();}

        this.timerID = window.setTimeout(f, this.nTimeout);

    }     

    ScreenSaver.prototype.onevent = function(e){

        this.screenSaver.signal();

    }     

    var saver;

    function initScreenSaver(){

        //blort;

        saver = new ScreenSaver({timeout:5000});   //无动作时间

    }

    window.onload = function(){

      initScreenSaver();

    }